The present invention relates to a control system for an internal combustion engine having a plurality of evaporative fuel paths.
Generally, a car has a fuel tank for storing fuel. Within the fuel tank, the fuel is evaporated to generate evaporative emission.
If the evaporative emission is discharged in the atmosphere, it will cause air pollution. Therefore, the evaporative emission is introduced into the air intake path through evaporative fuel paths or routes. The evaporative fuel is further discharged into the cylinders of the internal combustion engine for combustion.
By controlling the fuel flow in the internal combustion engine', the quantity of the fuel supplied from a fuel supplying device, such as a fuel injector or the like, is controlled so that an air-to-fuel ratio is held near a target air-fuel ratio.
In the conventional system, there is a problem that the air-fuel ratio of the mixture to be burned in the cylinder deviates greatly from the target value due to discharging of the evaporative fuel into the cylinder from the fuel tank or the charcoal canister.
It is an object of the present invention to provide a control unit for an internal combustion engine which can promptly burn the evaporative fuel generated in the fuel tank and which can minimize the influence of the evaporative emission on the control of the air-fuel ratio.